Figure 5. Map of the Ivanhoe basin area, showing the original known and inferred extents of the sedimentary basin, middle Miocene volcanic units, dates of various sedimentary and volcanic units, major post-sedimentation normal faults, and the late Eocene Carlin gold trend. Uncolored areas include areas of pre-Miocene basement rocks in the Tuscarora Mountains and post-middle Miocene sedimentary cover in Boulder and Kelly Creek Valleys; the extent of volcanic units beneath sediments in Boulder Valley is based upon exposures of identical volcanic units in the cliffs on either side of the valley. See Table 1 for geochronologic information. The modern digital elevation map is used as the base.